Backpacks have been used by people for many years to transport goods on their backs. There are three main types of backpacks, specifically internal frame, external frame and no frame backpacks. Internal frame backpacks have some sort of stiff structural element such as a metal pole or stay inside the backpack. The frame is often permanently attached to the fabric and is therefore not removable from the backpack. External frame backpacks have a frame on the outside of the backpack. No frame backpacks typically comprise a sack with straps, for example a Duluth backpack.
It is desired to have a backpack that is versatile in a number of respects. Backpacks typically have one fairly large compartment. Such a large compartment is desired because it may be needed to accommodate a tent, sleeping bag, sleeping pad, or other items which are fairly large in size. At the same time it is important that items in the backpack be found quickly. For example, bad weather requires quick access to rain gear. Mosquitoes require quick access to bug spray. Furthermore, it is simply desired to minimize the amount of time spent digging through the backpack looking for items even when not in a hurry. The large compartment makes it difficult to find items in the backpack and often a backpacker spends a significant amount of time removing the contents of the backpack to find a particular item.
It is also desirable to keep the contents of the backpack clean and dry. Wet clothes or other items in a harsh outdoor environment are uncomfortable at best and can be deadly. Most backpacks are designed to be merely set on their side on the ground when not on the backpackers shoulders. If the ground is wet, then the side of the backpack that is sitting on the ground gets wet. Furthermore, when the contents of the backpack are removed to find particular items, such contents must be placed on the ground where they will get wet and dirty.
For storage of backpacks when not in use, it is also desirable that the backpack be collapsible so that it takes up less storage space and makes for easy transport of the backpack.
U.S. Pat. No. 3,321,120 (Cunningham) discloses a backpack having four compartments. The partitions between the compartments are sewn or otherwise securely bonded into the sack. The Cunningham backpack must be placed on its side on the ground in order for the user to gain access to the compartments. Therefore, the side of the backpack on the ground will get wet if the ground is wet. Furthermore, the Cunningham backpack lacks versatility. The partitions cannot be removed or changed in position. Therefore, if the backpacker has a tent or other large item that doesn't fit in the compartments as set by the manufacturer, then the large item would have to be carried by someone else or strapped onto the outside of the backpack.
U.S. Pat. No. 2,792,980 (Brown) discloses a no frame shoulder pack made of a pliant material such as canvas. This shoulder pack has shelves. However, this pack will slouch over and not stand upright if not packed evenly throughout. One shelf will drop down onto the contents of the shelf below because there is nothing holding the shelf up. Furthermore, the user is confined to the exact number of shelves and spacing of shelves set by the manufacturer.
U.S. Pat. No. 2,517,757 (Adlerstein) discloses an internal frame knapsack with shelves fixedly attached to the frame. Again, this backpack lacks versatility. The user is restricted to the number of shelves and the shelf locations set by the manufacturer. It is also to be noted that the Alderstein backpack takes up considerable storage space when not in use.
U.S. Pat. No. 3,144,014 (Mantell Jr.) discloses a backpack with an integral camp stove. The backpack comprises an aluminum box with a single fixed shelf. Again, this backpack lacks versatility in that the shelf is not movable. Furthermore, the aluminum box takes up a significant amount of storage space when not in use.
It is therefore desired to have a backpack which includes the structural support of a framed backpack, that can stand upright while at the same time being compressible so that it can be easily stored taking up only a minimal amount of space. It is also desired to have a backpack that has compartments that are easily changed in size and number.